Power Factor Correction Calculator

Calculate the capacitor bank size needed to improve power factor to a target value, reducing reactive power charges.

kW

Required Capacitor Bank

55.3 kVAR

Current Reactive Power88.2 kVAR
New Reactive Power32.9 kVAR
Apparent Power Reduction28.1 kVA

Required Capacitor Bank vs Real Power

Power Factor Correction

Low power factor means the utility must deliver more current (and apparent power) than the load actually uses. Capacitor banks supply reactive power locally.

Formula

kVAR needed = kW x (tan(arccos(PF_current)) - tan(arccos(PF_target)))

Benefits

  • Reduced utility power factor penalties
  • Lower line current (smaller cables, less loss)
  • Freed transformer and distribution capacity
  • Most utilities penalize power factors below 0.90. Correcting to 0.95 is a common economic target.

    Example Calculation

    100 kW load at PF 0.75, correcting to PF 0.95.

    1. 01Current angle: arccos(0.75) = 41.41 degrees, tan = 0.8819
    2. 02Target angle: arccos(0.95) = 18.19 degrees, tan = 0.3287
    3. 03kVAR needed: 100 x (0.8819 - 0.3287) = 55.3 kVAR
    4. 04kVA reduction: 100/0.75 - 100/0.95 = 133.3 - 105.3 = 28.1 kVA

    Frequently Asked Questions

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